Wireless sensor networks (WSN) consist of a large number of small sensor nodes, usually spread out in hard accessible areas and communicating wirelessly. A sensor node Combines the abilities to sense, compute, and communicate to other nodes. The large numbers of nodes with minimum capacity devices operating in constraining and demanding real-world environments impede communication within and outside the network, making the process of implementing security in wireless networks exceptionally difficult and expensive. We discuss these difficulties and what is being done to overcome them in order to meet the ever-growing and popular wireless sensor networks. We conclude by considering several potential future directions for security solutions.